{
  "abstract": "Background\n\nOsteosarcoma is a heterogeneous bone malignancy in which malignant, immune, stromal, and bone-lineage cells form a complex microenvironment. Clinical activity of immune-checkpoint blockade has remained limited in advanced osteosarcoma, motivating cell-type-resolved investigation of the tumor microenvironment while avoiding mechanistic overinterpretation of cross-sectional transcriptomic data.Methods\n\nSingle-cell RNA-sequencing data from primary osteosarcoma were obtained from GEO (GSE162454; six patients) and analyzed with Scanpy using quality filtering, normalization, highly variable gene selection, principal component analysis, neighborhood graph construction, UMAP, Leiden clustering, and marker-based cell-type annotation. Seven transcriptional programs and ligand-receptor communication scores were evaluated. An independent bulk osteosarcoma cohort with metastatic status and overall survival annotation (GSE21257; n = 53) was used for differential expression, cross-platform comparison, and survival analysis. RT-qPCR was performed in primary human osteoblasts exposed to MG-63 osteosarcoma-conditioned medium.Results\n\nAfter quality control, 44,189 cells with 25,473 detected genes were retained. Leiden clustering resolved 23 clusters annotated into 11 cell types; myeloid cells (34.0%) and osteoblasts (16.6%) were the largest populations. Osteoblasts showed the highest osteogenic program scores, whereas myeloid cells showed the highest inflammatory and immune-evasion scores. Reclustering of osteoblasts, osteocytes, and mesenchymal stromal cells resolved seven stromal subclusters, but pairwise co-expression between representative osteogenic and inflammatory genes was generally weak. Ligand-receptor analysis highlighted MIF-CD74, SPP1-CD44, and SPP1-ITGAV as the strongest scored interactions. In GSE21257, 333 genes differed between metastatic and non-metastatic tumors at FDR<0.05; the inflammatory module was lower in metastatic tumors, whereas the osteogenic module was not significantly different. The single-cell osteoblast effect showed only modest concordance with the bulk metastatic effect (Spearman rho = 0.254), and a 20-gene osteoblast signature did not stratify overall survival (log-rank p = 0.968). In vitro, osteosarcoma-conditioned medium reduced RUNX2 and SP7 and increased SOST and RANKL expression in primary osteoblasts.Conclusion\n\nIntegrated single-cell and bulk transcriptomic analyses identify lineage-specific osteogenic, inflammatory, and communication programs in osteosarcoma but also demonstrate limited cross-platform generalizability of osteoblast-centered signatures. The RT-qPCR experiment supports an osteoblast transcriptional response to soluble factors from MG-63 cells, but it does not establish a specific immunosuppressive mechanism or prognostic biomarker. These findings should therefore be considered hypothesis-generating and require independent single-cell, spatial, and functional validation.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Orthopedics, Zhongda Hospital, Southeast University , , ,",
    "Department of Joint Surgery, The Fifth Affiliated Hospital of Southern Medical University , , ,"
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 2,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Zhiwen Zhou"
    },
    {
      "affs": [
        1
      ],
      "name": "Zhijun Li"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/1e2g2htcwnx49.bib",
  "cited_by": 0,
  "doi": "10.3389/fgene.2026.1927885",
  "fulltext_url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13719136/?tool=EBI",
  "id": "1e2g2htcwnx49",
  "issns": [
    "1664-8021"
  ],
  "landing_url": "https://europepmc.org/article/PMC/PMC13719136",
  "language": "eng",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "heading",
      "Original Research"
    ],
    [
      "openalex",
      "2740|Sarcoma Diagnosis and Treatment"
    ]
  ],
  "openalex": "W7222046926",
  "pdf_url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13719136/pdf/?tool=EBI",
  "pmcid": "PMC13719136",
  "pmid": "42960375",
  "published": "2026-10-16",
  "publisher": "Frontiers Media SA",
  "ris": "https://research.draconitic.com/paper/1e2g2htcwnx49.ris",
  "sources": [
    {
      "first_seen": "2026-10-31T00:20:37Z",
      "native_id": "PMC:PMC13719136",
      "source": "europepmc",
      "url": "https://europepmc.org/article/PMC/PMC13719136"
    },
    {
      "first_seen": "2026-11-01T00:20:52Z",
      "native_id": "MED:42960375",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42960375"
    },
    {
      "first_seen": "2026-11-02T12:23:01Z",
      "native_id": "PMC13719136",
      "source": "pmc",
      "url": "https://doi.org/10.3389/fgene.2026.1927885"
    }
  ],
  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2740|Sarcoma Diagnosis and Treatment",
      "subfield": "general"
    }
  ],
  "title": "Single-cell and bulk transcriptomic characterization of the osteosarcoma microenvironment reveals lineage-specific programs and inflammatory differences associated with metastasis",
  "title_text": "Single-cell and bulk transcriptomic characterization of the osteosarcoma microenvironment reveals lineage-specific programs and inflammatory differences associated with metastasis",
  "type": "peer-reviewed",
  "updated_at": "2026-11-02T12:23:01Z",
  "url": "https://research.draconitic.com/paper/1e2g2htcwnx49",
  "venue": "Frontiers in genetics",
  "versions": []
}